I hate this... Vacuum Water Cock.. in the heater/air conditioning??!!

[PrOxLaMuS©]

After my leaking problem of antifreeze all over my passenger floor.. I found something interesting....

after 4 hours of removal and finding a good place to take a picture... here is the complete Heater **** and Vacuum Water **** assembly along with the hoses which go to the heater core.. and out the firewall.

However, I bought a new heatercock.. since it was leaking.. but somethign else is too..

can anyone help me out??

In the picture.. it's along the top.. goldish and looks like a UFO disk thinggy. It is a vacuum and has a diaphram in it.. and connects to the heater/cool controls.

What does it do? Vacuum Water ****...

help! my car is taken apart!@

[Zedrally]

What model is from?

[mdbrandy]

It's from your '78 280Z, right? The 78 that I just took apart didn't have one of those. Looking through the factory manual (do you have the factory manual on yours?) it looks like it is a vacuum actuator valve for the factory air conditioning. Do you have factory air? Is it the vacuum **** in the attached drawing?

[mdbrandy]

I looked at the drawings more, and it looks like it is that vacuum valve. It shuts off coolant flow to the heater core if the HVAC controls are in the vent or AC position, and lets coolant flow through the core in heat positions. There are about 6 other drawings in the manual similar to the one I posted that show the position of the vacuum valve and vent flaps in various HVAC control positions.

Hope this helps.

[PrOxLaMuS©]

I have the Factory Service Manual from Nissan...

and yes it's for my 1978 280Z....

it has the factory air conditioning.. and like the diagram you attached... it is called the Vacuum ****... above the water ****...

i really hate it under the dash.. i hate it

[mdbrandy]

I guess I'm not sure what your question is...

[sblake01]

I too have a 78. It doesn't have factory air but it has the dealer installed ARA system. I had a similar problem. There are many parts under there that can cause a leak. After replacing hoses and clamps and still finding leaks, I took it to my friends shop in Upland. I figured that everything under there was 25 years old and it wouldn't be a bad idea to replace it all. I had the heater core and all the attending valves, hoses, clamps, connectors, and blower motor replaced. I cost me about $450. No more leaks, heater and AC work better, peace of mind. Well worth it!

[PrOxLaMuS©]

My question was.. what does it do?

Also is there a rubber seal inbetween the Vacuum Water **** and the mounting plate?

[mdbrandy]

Originally posted by PrOxLaMuS©

My question was.. what does it do?

Also is there a rubber seal inbetween the Vacuum Water **** and the mounting plate?

Several posts ago, I said:

It shuts off coolant flow to the heater core if the HVAC controls are in the vent or AC position, and lets coolant flow through the core in heat positions. There are about 6 other drawings in the manual similar to the one I posted that show the position of the vacuum valve and vent flaps in various HVAC control positions.

Essentially the valve doesn't let hot water into the heater core when you have either the vent or AC active.

I don't know about the rubber seal.

Good luck.

[PrOxLaMuS©]

...

sorry... i just thought the part you mentioned was something different since you called it something else...